Lunch box



FIG. 1 is a perspective view of a lunch box;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left elevational view thereof;

FIG. 5 is a right elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines shown in the drawings illustrate portions of the lunch box that form no part of the claimed design. 

CLAIM The ornamental design for a lunch box, as shown and described. 